Group A strep is the more common name for the bacterium Streptococcus pyogenes, which most people encounter daily. It's a part of our normal skin flora and is all around us out in the world.
While many people will come into contact with strep A and not get an infection, a surge in strep A infections in children in the years following the COVID-19 pandemic drew attention to the significant dangers of this common bacteria.
There are multiple Streptococcus strains, and group A is one of the most common. It's highly contagious and spreads in a number of ways, causing a variety of infections.
Strep A can spread through airborne droplets, skin contact with contaminated surfaces or body fluids (nasal discharge, wound drainage), or contaminated food.
Group A strep is the most common bacterial cause of inflammation of the back of the throat. Symptoms of strep throat include throat pain, headaches, fevers, and chills. Many people develop white patches in the back of the throat or tiny red spots on the back of the roof of the mouth.
Strep throat can progress and cause complications if left untreated. Oral antibiotics are typically the treatment of choice.
Scarlet fever can develop as a complication of strep throat or result from a skin infection. It appears as a blanching red rash that feels like sandpaper. On its own, the rash is not dangerous, but it is a tell-tale sign of a group A strep infection that requires rapid treatment.
Scarlet fever usually develops within two to three days of a strep infection, but it can take as long as seven. The rash first develops on the trunk, groin, and underarms and spreads to the extremities. Other symptoms of scarlet fever include fever, sore throat, swollen glands, and strawberry tongue. Historically, scarlet fever was considered a severe disease. While antibiotics have made it milder and more manageable, serious complications can arise when the condition is untreated or if treatment is delayed.
The skin lesions that occur with impetigo usually appear as red plaques with yellow crusts that may be itchy or painful. They are most commonly seen on the face but can show up on any part of the body with a cut, abrasion, or other damage, and they're highly contagious. Most cases of impetigo are caused by staph aureus, but 10 percent are caused by group A strep and another 10 percent by a combination of the two bacteria.
In many cases, impetigo resolves on its own in two to three weeks, but if group A strep is the cause, there is a greater risk that the person will develop renal failure, which can appear one to two weeks after the initial infection. If medical attention is needed, impetigo will be treated with antibiotics.
One of the more severe conditions that group A strep can cause is necrotizing fasciitis. The infection starts in the muscle tissue, then spreads outward to the skin, which begins to break down a few days later. People with necrotizing fasciitis are often in extreme pain and should be monitored in an intensive care unit.
Surgery is the primary treatment for this condition, and the earlier the person has surgery, the better the outcome. The surgeon will remove all of the dead and infected tissue. Recovery is a long process, and mortality rates with this condition are higher than 30 percent. While other bacteria can cause necrotizing fasciitis, cases caused by group A strep have poorer prognoses.
Most cases of cellulitis are caused by group A strep. The primary symptom is a red, warm, swollen patch of skin that is tender to the touch. When the condition is caused by group A strep, there is a higher chance of more invasive disease. Cellulitis can appear on any part of the body, but it is most common on the legs.
If identified and treated early, cellulitis can improve within 48 hours. Once a person has had cellulitis, they are more likely to get it again. About 20 percent of people have a yearly reoccurrence, while the overall reoccurrence is close to 50 percent. The outlook for cellulitis is good, but there can be complications.
Toxic shock syndrome was typically associated with the use of high-absorbancy tampons and menstruating women, but these tampons were taken off the market and, today, experts pay closer attention to cases stemming from soft tissue infections, post-surgical infections, and burns. When toxic shock syndrome is caused by group A strep, it usually results from cellulitis or necrotizing fasciitis.
Symptoms come on fast and include rash, fever, and low blood pressure, but these may be preceded by headache, sore throat, nausea, or vomiting. Patients with toxic shock syndrome must be admitted to an ICU for medical management. This condition is very serious; when caused by group A strep, the fatality rate may be higher than 50 percent.
If strep throat or scarlet fever is not treated adequately, it can progress to rheumatic fever. This condition is an inflammatory disease that most commonly affects children between five and 15. Doctors do not know the link between strep and rheumatic fever, but it may result because group A strep tricks the body into attacking its own tissues.
Rheumatic fever causes inflammation in the heart, skin, joints, and central nervous system, and symptoms usually appear two to four weeks after strep throat. The major complication of rheumatic fever is its ability to damage the heart valves, which leads to heart failure.
Poststreptococcal glomerulonephritis is a kidney condition that can occur as the result of a group A strep infection. It mostly affects young children one or two weeks after strep throat or six weeks after impetigo. Symptoms of this condition include hypertension, swelling of the face or hands, and bloody urine, but half of the children who have it are asymptomatic.
Most people recover within a few weeks without long-term complications. However, in rare cases, kidney damage may develop.
Specific treatment for strep A depends on the nature and severity of the infection, but all infections from group A strep are bacterial, so antibiotics are the first option. Penicillin-based antibiotics are highly effective at treating strep A infections, as are other classes of antibiotics, like cephalosporins.
People with strep A infections can take antibiotics orally, but an IV is necessary when the infection is systemic or severe.
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